Enable notify in the master zone

Just to make sure that the slaves get notified.
Set more sensible timeout values

These values were way off. Especially a retry higher than TTL does
not make sense..
Make sure that the master node has slaves_names/ips set

Without the dup, it deletes the master node from the nodes.each
loop below, so it doesn't set anything..
Merge pull request #114 from dirkmueller/master

Multi-DNS fixes
Disable notify in the slave zone

Slaves should not notify themselves anymore.
Fix syntax error

'ipv-6-address' is not a valid IPv6 address.